With smart mobile devices becoming more prevalent, location sensing technology for these devices has become widespread. Outdoor location sensing is well-served by satellite-based location technology, but satellite signals are undependable indoors, so other location techniques must be used. A variety of indoor location techniques have been developed, most of them relying on determining the mobile device's position relative to other indoor devices whose positions are known. Such relative positioning is typically based on communicating with each of the other devices, and using either signal propagation times or received signal strength indicators to estimate the distance from each device. Triangulation can then be used to determine position in either two or three dimensions.
Because the mobile device may be moved to a new location, it may periodically communicate with the other devices to update its distance from those devices. That movement may also take it out of range of some of the current list of devices whose positions are known, and/or bring it into range of other devices whose positions may then become known. Both of these factors mean that the device periodically scans the relevant wireless channels. Current scanning techniques typically use the same algorithms that are used when searching for new network controllers. However, these algorithms are typically based on the assumption that it's desirable to find every reachable network controller, and that scanning will be done relatively infrequently. These consume too much power to be directly applied to frequent location sensing.
Thus there are general needs for wireless devices and methods for improved and more efficient scanning in wireless networks, including those that reduce power consumption.